Hi, I’m thinking of building a handheld burst disk hybrid which operates with a 4x mix of propane and air. Here are the specs: schedule 40 steel pipe construction, 3” x 16” chamber, golf ball size x 40” barrel, spark plug and modified arc lighter ignition (or nichrome wire, a 9 volt, and a toggle switch). Can I fire this without a stand without falling over? Or do I need to make a stand for it? I’m considering a muzzle brake because it might actually help because of the amount of gasses from a hybrid (I think so anyway). I’m not a very large person (I’m 13) so the recoil might be a little much for me.

Plugging your specifications into HGDT gives us the following:



1785 ft lbs (I assumed a 1 lb projectile) of muzzle energy is less than what you would expect for a typical 12 gauge shotgun load.

Here's a 13 year old kid shooting a much, much more powerful 10 gauge shotgun:



If it's well supported and you lean into it properly, it shouldn't knock you over.

Ok, thanks. I guess it wouldn’t kick much more that the dumpster cannon (a bad idea!).

And if my metering pipe was made out of 1/2” schedule 40 steel, how long would it need to be?

Do the math

regarding recoil, I use http://www.shooterscalculator.com/recoil-calculator.php

Muzzle energy is related to recoil energy BUT things like propellant mass and momentum are significant. I plugged in the numbers for the 7000 grain projectile at 339fps in a 10 lb launcher and the recoil was considerable with zero propellant.

Ok, thanks.

Anatine Duo wrote:the recoil was considerable with zero propellant.

That's why recoilless guns work